A nc-titania modified cellulose Janus membrane for unidirectional water penetration and fog collection

Abstract

Janus membranes are ideal devices for sustainable fog collection to help alleviate the global water shortage. However, it remains challenging to obtain Janus membranes with sufficient flexibility, low cost, chemical stability and anti-pollution properties. In this work, flexible Janus membranes based on cellulose substrate were fabricated for effective fog collection. We undertook a detailed study of the formation mechanisms of the Janus membranes, which contain an asymmetric growth of titania and a single-side hydrophobic modification. The proper thickness and discontinuity of the hydrophobic layer allow unidirectional water penetration, and the punched holes provide rapid water conveyance channels. The perforated Janus membranes showed the highest fog collection efficiency (∼3 times as much as that of a totally hydrophilic membrane) of the various types that were prepared. Furthermore, the Janus membranes exhibit desirable anti-acid, anti-pollution and reusability properties, which demonstrate application potential in complicated practical settings.